Increased levels of Aß42 decrease the lifespan of ob/ob mice with dysregulation of microglia and astrocytes.

Clinical studies have indicated that obesity and diabetes are associated with Alzheimer's disease (AD) and neurodegeneration. Although the mechanisms underlying these associations remain elusive, the bidirectional interactions between obesity/diabetes and Alzheimer's disease (AD) may be involved in them. Both obesity/diabetes and AD significantly reduce life expectancy. We generated AppNL-F/wt knock-in; ob/ob mice by crossing AppNL-F/wt knock-in mice and ob/ob mice to investigate whether amyloid-ß (Aß) affects the lifespan of ob/ob mice. AppNL-F/wt knock-in; ob/ob mice displayed the shortest lifespan compared to wild-type mice, AppNL-F/wt knock-in mice, and ob/ob mice. Notably, the Aß42 levels were increased at minimum levels before deposition in AppNL-F/wt knock-in mice and AppNL-F/wt knock-in; ob/ob mice at 18 months of age. No differences in the levels of several neuronal markers were observed between mice at this age. However, we observed increased levels of glial fibrillary acidic protein (GFAP), an astrocyte marker, in AppNL-F/wt knock-in; ob/ob mice, while the levels of several microglial markers, including CD11b, TREM2, and DAP12, were decreased in both ob/ob mice and AppNL-F/wt knock-in; ob/ob mice. The increase in GFAP levels was not observed in young AppNL-F/wt knock-in; ob/ob mice. Thus, the increased Aß42 levels may decrease the lifespan of ob/ob mice, which is associated with the dysregulation of microglia and astrocytes in an age-dependent manner. Based on these findings, the imbalance in these neuroinflammatory cells may provide a clue to the mechanisms by which the interaction between obesity/diabetes and early AD reduces life expectancy.

Upregulated expression of a subset of genes in APP;ob/ob mice: Evidence of an interaction between diabetes-linked obesity and Alzheimer's disease.

Clinical studies have indicated that obesity and diabetes are associated with Alzheimer's disease (AD) and neurodegeneration. However, the mechanism by which obesity/diabetes and AD interact with each other and contribute to dementia remains elusive. To obtain insights into their interaction at molecular levels, we performed gene expression analysis of APP;ob/ob mice, which were generated by crossing transgenic AD model mice (APP23 mice) with ob/ob mice, which are obese and mildly diabetic. The Aß level in these mice was reduced compared with that in pure APP mice. However, we identified a cluster of genes (cluster 10) upregulated in APP;ob/ob mice but not in either APP or ob/ob mice. Interestingly, genes upregulated in the human AD brain were enriched in cluster 10. Moreover, genes in cluster 10 formed a network and shared upregulated genes with a cell model of neurodegeneration and other models of neurological disorders such as ischemia and epilepsy. In silico analyses showed that serum response factor (SRF), recently identified in a single-cell analysis of human brains as a transcription factor that can control the conversion from healthy cells to AD cells, might be a common transcriptional regulator for a subset of cluster 10 genes. These data suggest that upregulation of genes uniquely associated with APP;ob/ob mice is an evidence of the interaction between obesity/diabetes and AD.

Serum albumin/globulin ratio is associated with cognitive function in community-dwelling older people: The Septuagenarians, Octogenarians, Nonagenarians Investigation with Centenarians study.

AIM: The objective of this study was to clarify the relationship between cognitive function and the serum albumin/globulin ratio (A/G ratio) in community-dwelling Japanese older adults. METHODS: Randomly extracted residents in both urban and rural parts of Japan were enrolled in this study. A total of 1827 participants with a mean age of 70 or 80 years were recruited. A venue survey method was carried out with comprehensive studies, including interviews, blood collection, physical examination and cognitive function tests. RESULTS: Univariate analysis showed a significant positive correlation between the total Japanese version of the Montreal Cognitive Assessment score and the serum A/G ratio at the age of 70 and 80 years, in which better cognitive function was associated with a high serum A/G ratio. Multiple regression analysis with the total Japanese version of the Montreal Cognitive Assessment score as the dependent variable showed that the serum albumin level, serum globulin level, serum A/G ratio, C-reactive protein, years of formal education and sex were related to the Japanese version of the Montreal Cognitive Assessment total score at the age of 70 years, and that the serum albumin level, serum globulin level, serum A/G ratio, C-reactive protein, years of formal education and stroke were related at the age of 80 years. The serum A/G ratio showed a better correlation than the serum globulin levels at the age of 70 and 80 years (70 years: ß = 0.131 vs -0.111, 80 years: ß = 0.108 vs -0.071). CONCLUSIONS: We found a correlation between cognitive function and the serum A/G ratio in community-dwelling older people, suggesting that nutritional status and chronic inflammation might influence cognitive function. Geriatr Gerontol Int 2019; 19: 967-971.

Disease-associated polymorphisms in 9p21 are not associated with extreme longevity.

AIM: The 9p21 region has been pointed out by the genome-wide association studies as a hot spot for disease-associated variants. Most of the diseases linked with the locus are aging-related conditions, such us cardiovascular disease, diabetes and cancer. Centenarians are known to present a reduced risk and delayed onset for these conditions. Here, we aimed to assess if the 9p21 variants contribute to this protection by possibly altering basic aging mechanisms. METHODS: We genotyped 15 tag single-nucleotide polymorphisms (SNP) along the CDKN2A/B/ANRIL locus in 1505 individuals. The participants were divided in three groups: centenarians, septuagenarians and young controls. Centenarians were 593 participants (age range 100-116 years, mean 105.9 years), septuagenarians were 434 volunteers aged between 69 and 71 years (mean 70.1 ± 0.9 years) and the 478 young controls were under the age of 50 years (range 14-50 years, mean 41.8 years). We genotyped the SNP rs1333049 in an additional sample of 231 coronary artery disease patients to confirm the 9p21 association. RESULTS: The leading coronary artery disease-associated SNP rs1333049 was associated with coronary artery disease; however, none of the 9p21 SNP evaluated in the present study were associated with extreme longevity. CONCLUSIONS: Our findings suggest that the 9p21 disease-associated polymorphisms do not contribute to the life-long protection from cardiovascular and other age-related diseases observed in centenarians. It is likely that this protection is mediated by mechanisms different from the ones underlying the 9p21 association.